INTRODUCTION- GALILEO GALILEI

Galileo Galilei was born on February 15, 1564 in Pisa, Italy. He grew up during the Renaissance. During this time, people were very open to new ideas in math, science and the arts. Also, many new books were being printed, making it easier to get ideas across. During his life, he discovered many important things about astronomy, math and science. He discovered that the weight of the "bob", or the weight on the end of a string did not affect the length of the swing, but the length of the string did. With this information, he made the first clock. Later on, he disproved Aristotle's law that heavier things fall quicker by dropping two objects of different weights off the leaning tower of Pisa and seeing that they fell at the same time. After the invention of the telescope, he discovered the craters on the moon, Jupiter's moons, and many other very important things about the universe. He also stated that Earth was not in the center of the universe, and that the sun was. In 1624, he was called to Rome for the second time. The reason for this was that he had written a book in which he said that the Earth was not in the center of the universe. He was asked by Pope Urban to write a new book and at the end agree with Aristotle, the man who had believed that the Earth was in the center. He did write the book, but at the end wrote that Aristotle was wrong. He was then asked to stand trial for heresy, a serious crime against the church. He was put under house arrest. Galileo continued his experiments, but he got an eye infection, and on January 8, 1642, died. He made many important discoveries about force gravity and motion. He helped move science forward. Galileo Galilei changed the world.



Moon Observations

As you can see on these pictures, the moon has craters and mountains. Galileo discovered these by observing the moon through
his telescope. Aristotle had thought that the moon was a perfect sphere, but as Galileo discovered, the moon had mountains and craters.

Jupiter and its Moons

See those bright spots around Jupiter? Those are not stars, but moons. They orbit around Jupiter just as our moon orbits around us. Galileo discovered Jupiter's
moons when he was observing the night sky. He noticed spots on Jupiter's surfice. Every night, the spots would move a little. If you look closely at the pictures
above, you can see that the moons are in different places in each of the pictures. He named the moons after the Grand Duke Cosimo II because he was his new boss.
The fact that there were moons orbiting Jupiter went against Aristotle because he had said that all things orbit the Earth, but Galileo had discovered something that
didn't. Also, because everyone had said that it was impossible for the moon to orbit earth and the earth orbit the sun at the same time, but because Jupiter had
moons that orbited it, so could earth.

Saturn's Rings

Did you know that Saturn had rings? It does! This picture is
of Saturn, and the fuzzy stuff around it are its rings. Galileo
discovered that Saturn had rings.

Sunspots on the Sun

In the picture of the sun above, there are dark spots. They are called sunspots. Christopher Scheiner thought that they were
tiny planets orbiting the sun very close to its surface. Galileo disagreed, and some said that he was lessening their hope of
heaven. This was disagreeing with Aristotle because he had said that the sun was perfect, and with spots on it, it is not
perfect anymore.

Venus has Phases

Galileo also discovered that venus had fases. This supported Copernucus' ideas because Copernicus
had said that the sun was at the center. If the sun was at the center, than it was possible for venus to
have fases. Since both Earth and Venus orbit the Sun, it is possible for Venus to be in between the
Earth and Sun. When this happens we experience a "new venus" just like a new moon.

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